1. Field of the Invention
This invention relates to light measuring devices for single lens reflex cameras, and, more particularly, to light measuring devices for single lens reflex cameras which have a plurality of reflecting regions in an auxiliary mirror for light measurement positioned in rear of the movable mirror.
2. Description of the Prior Art
In the past several proposals, concerning the light measurement by an auxiliary mirror behind the movable mirror of the single lens reflex camera, have been made in anticipation of the possibility of the light sensitive element of this type light measuring system also serving as a light sensitive element for the light reflected from the photographic film.
For example, in Japanese Laid-Open Patent Sho 50-82399, a portion of the movable mirror for the finder is made semi-transmissible and is rearwardly followed by a plain mirror or a concave mirror which following mirror directs part of the light from an object to be photographed to the light sensitive element. Another proposal in Japanese Laid-Open Utility Model Sho 53-148637 is that, in the same arrangement, the reflection surface of the auxiliary mirror, located behind the movable mirror for the finder, is imparted with a directional property to correct the light sensitivity distribution.
In these types of light measuring devices, however, the determination of the light measuring range has to be made in the manufacturing stage, therefore, it is impossible for the photographer to change the light measuring range. In back lighting scenes or in a theater using many spot lights, it very often happens that the camera must be operated so that the photographer has a choice between a center-weighted partial field of view light metering mode and an overall field of view or average light metering mode. Therefore, many photographic situations where the light metering system of such fixed light measuring range is felt inconvenient have been encountered.